WANT:

1. psychotic and freaky over the heroine aka the main girl in the story, but still genuinely loves her
2. smut
3. does whatever the heroine wants
4. can be a stalker
5. a bishounen
6. there can be reverse harem

DO NOT WANT:

1. yaoi/shounen ai
2. rape/abuse
3. useless/dumb heroines (but it's okay if you can't find those with smart heroines, recommend it anyway)

Dengeki Daisy? Well, there's no smut tho, but it might be something you're looking for...
or Hapi Mari maybe

Sorry if it doesn't suit the requirements, hope it still helps

Well this is more josei than shoujo and isn't very smutty, but Abide in the Wind (Naver webtoon) should meet most of your requirements.

Cheese in the Trap is josei, but it fits the other criteria. The female lead is smart and intuitive, and the male lead is merciless to anyone he dislikes or who's a threat to the female lead. No smut though.

Watashi no Megane-kun fits most of your requirements except 3 and 6, as well as Bokura no Koi wa Shi ni Itaru Yamai no You de fits 1, 2 and 4. A oneshot not smutty called Risou no Kareshitachi. Hope you liked them, I happen to be a male yandere fan 🙂 . And oh, it it interest you, you can check out the otome game (you can get in your app store or goole play called Starstruck Love. Now that's a yandere 😀

I'm in idol hell T.T

(So I just answered a similar post a few days ago, so I just copied and pasted what I wrote.)

So For Extremely Possessive/Yandere* Guys:
Aishite Kudasai, Sensei
100% Perfect Girl (warning: This has a lot of drama in it)
The World Is Still Beautiful
Metronome
Miniamaru Kareshi
The Result of Being Reincarnated is Having a Master-Servant Relationship with the Yandere Love Interest
Sensei no yasashi koroshi kata
Raise wa Tanin ga Ii (Warning: This contains Adult Content)
Yandere-kei Otomege no Sekai ni Tensei shite shimatta you desu
Risou no Kareshitachi (This is only a oneshot though)
Bokura no Koi wa Shi ni Itaru Yamai no You de (Warning: This contains Smut)